In an evolved packet core (EPC) network, a logical network element service gateway (S-GW) and a packet data network gateway (P-GW) are usually deployed in an integrated way, forming a unified gateway (UGW). The UGW is further divided into a UGW-C (hereinafter referred to as a control plane gateway) and a UGW-U (hereinafter referred to as a forwarding plane gateway) based on an idea of control and forwarding separation.
Based on a current charging architecture defined by the 3rd Generation Partnership Project (3GPP), a gateway (for example, UGW) in an EPC network can normally provide a charging trigger function (CTF) in the charging architecture. Therefore, the CTF may be split based on the idea of control and forwarding separation, so that some functions of the CTF are placed on a control plane gateway, and the remaining functions of the CTF are placed on a forwarding plane gateway. In the charging architecture, an offline charging system and an online charging system are mutually independent charging systems; and on the forwarding plane gateway resulting from splitting of the CTF, there is a large difference in trigger conditions between the offline charging system and the online charging system. Therefore, an offline charging function and an online charging function need to be implemented separately on the forwarding plane gateway. Specifically, the control plane gateway may deliver both an offline charging parameter and an online charging parameter to the forwarding plane gateway, and the forwarding plane gateway collects charging statistics and reports charging results separately in offline and online statistics and reporting methods.
However, in the foregoing charging architecture, the forwarding plane gateway needs to separately implement the offline charging function and the online charging function, and therefore the offline charging function and the online charging function cannot be unified on the forwarding plane gateway. As a result, it is highly complex to implement the forwarding plane gateway and a control interface between the forwarding plane gateway and the control plane gateway.